Physical Layer ARQ (HARQ) and cell switching are two link-adaptation techniques that are employed by the 1xEV-DV forward link standard. Cells are comprised of base transceiver stations (BTS) in wireless environments which have lower traffic and sectors, which subtend an angular portion of a full periphery, such as 120°, in wireless environments having higher traffic.
The hybrid automatic repeat request (HARQ) protocol uses an adaptive automatic repeat request (ARQ) technique for retransmission combining.
Cell switching is a handoff technique that allows the mobile terminal (MS) to identify an optimal serving cell pilot channel based on measurement with C/I being a strength ratio of the carrier signal to the interference.
In the 1XTREME/1xEV-DV proposal, fast cell site selection (FCSS) is proposed to ensure mobility. When a mobile moves from one cell to another cell, a central entity Network Convergence Function (NCF) is used to coordinate multiple cells in the active set. During soft handoff, a NCF provides the same data units (PDUs) to all of the cells in the active set (flooding). However, only one cell delivers the PDUs to the MS. When the MS moves from one cell to another in the active set, the MS echoes the most recently received NCF sequence number so that the new cell can resume the data transfer without delay.                1. FIG. 1 shows an example of a prior art cell switching operation. Cell a and cell b both are in the MS's active set. Prior to switching cell a sends the data frames to the MS by the Forward Shared Channel (F-SHCH). Upon a measurement threshold, the MS may decide to request new cell switching by sending a request on R-CCH to request cell switching to cell b. The serving cell a serves the MS, before the cell switching, with the forward and reverse link channels. The target cell b is the cell chosen for the transmission after the cell switching is completed. An active set for the Forward Packet Data Channel is updated to cell a based on the pilot strength feedback from the MS. All cells in the active set (only two have been illustrated for convenience purposes) are eligible for forward link cell switching.        
In FIG. 1, the Abis interface (the Abis interface is between the base station controller (BSC) and the cells) flooding occurs during, for example, the soft handoff of 1XTREME/1xEV-DV FCSS procedure. This problem significantly affects the BSC and cell performance. During soft handoff, both Abis links between the BSC and cell a and cell b are active as indicated by the bidirectional arrows therebetween. Flooding involves substantial transmission overhead, memory requirement inside the cells and a centralized management entity which manages the large sequence frame numbering.
After the MS has signalled the BSC with an indication on R-CCH as indicated in FIG. 1 that the MS wants to switch receiving forward link transmissions from cell a to cell be, the BSC transmits the data packets simultaneously to both the serving and target cells until handoff is complete. The simultaneous use of the Abis resources by the BSC for the serving and target cells and the radio resources from the serving and target cells is wasteful especially when data rates are high such as for 1 xEV-DV (around 4 Mbps).